Laying a concrete/screed decorative hearth base.

[bcjames]

Hello,

We have recently uncovered the original fireplace in our living room. This is part of a bigger restoration project, including replastering with lime and refitting a cast iron fireplace and log burner.

We are planning a raised, tiled decorative hearth, on top of the concrete floor that adequately forms the constructional hearth.

That means I need approximately a 50mm raised base on which to tile on to. I've been reading up on pouring it in concrete, but it seems that 50mm is too shallow for concrete to be strong enough. I also have concerns about it being overly rigid, and most of the 'recipes' I've seen promote adding lime to the mixture to add flexibility. As ever, breathability is a consideration, although there is not really any damp.

This picture shows much of the area, although it will extend further to the left and right.



The log burner is planned for some time next year, by a suitably qualified engineer, but the decorative hearth forms part of this years decorating plans.

Any ideas on something that I can use to build approx 1m square, 50mm tall, and be suitable for a cool hearth log burner base in a Victorian property would be greatly appreciated! As would any recommendations on techniques, as it's my first attempt at something like this.

James

 

[bushmins]

That original base looks cracked to buggery and could be on a wood base. I would dig it all up and relay. That way you could then put new concrete down after filling the space with rubble or bricks, raising it to what ever height you require.

Else you could just skim it and get one of those large ready made granet/marble/whatever bases. Make sure the skim is nice and flat. Although I have never done it, you could lay some steel in the conecte skim to strengthen it up...possibly. If it was me I would dig it up.

 

[bcjames]

Apologies for the slow reply.

The bit in the alcove is quite solid, and is made from bricks, hence the lines. There's a bit of mess on top that needs clearing out. I guess I could remove those bricks to make the back hearth deeper. The rest of the floor is concrete, with a smoother screed-type finish under the carpeted area. There's no wood around. The front basement was filled in some time in the 1970's, so there's about 7ft of concrete under everything you see in that photo.

The front hearth I removed was 1 brick tall with slate on top, and the back was the same height but in concrete.

The plan is to tile the new hearth with some Victorian reproduction tiles like the ones on the books in the photo, rather than a stone/slate.

 

[Sin_Chase]

Deep fill self leveling compound?

 

[Scrutinize]

@bcjames

You want a waterproof mortar/concrete & SBR based screed as the initial layer to fill in the cracks and the very deep spots in case there is damage to the dpm or no proper dpm (without knowing house age I'm assuming worse case). Keep this moist whilst drying to prevent cracks.

Then cap with self levelling compound to achiveve the matching finished floor level.

 

[milgo]

For 50-60mm a normal sharp sand screed will work just fine. You could build a simple frame or some rails to ensure it's nice and level.

I levelled the entire floor downstairs in my house and used a liquid surface DPM including inside the fire place. Under my log burner I have cement board screwed into the concrete floor on a bed of tile adhesive. I then tiled the board. Most people fit small stoves (less than 5kw if memory serves correctly) designed to produce little heat underneath. If that's the case then it doesn't have to be anything fancy .